Radiator cap

ABSTRACT

A radiator cap adapted to allow coolant to forcibly be added to the interior of the radiator while the cap remains attached thereto. The cap includes the usual cap body that grips the filler neck for removable attachment thereto and a pressure plate assembly including a gasket and having a spring for yieldably urging the gasket against a seat portion of the filler neck. The inventive cap also includes an outer tubular bypass communicating the interior of the radiator with the exterior thereof and a lower check valve selectively occluding the outer bypass. The lower check valve is automatically opened to admit air/fluid to pass into the radiator when the pressure therein drops below atmospheric pressure, i.e., the air/fluid passes through the outer bypass. The lower check valve may also be automatically opened by forcing fluid through the outer bypass thus allowing coolant to be admitted to the radiator without removing the cap therefrom. An alternate embodiment additionally includes an upper check valve also selectively occluding the outer bypass. The upper end of the outer bypass is provided with a transverse aperture disposed above the upper check valve. The aperture is communicated with a recovery overflow tank and coolant is allowed to pass one way only through this aperture, i.e., from the tank into the radiator.

United States Patent [191 Tusing [4 Oct. 7, 1975 RADIATOR CAP [76] Inventor: Arthur P. Tusing, P.O.,Box 64, Dell,

Ark. 72426 [22] Filed: Jan. 29, 1974 [21] Appl. No.: 437,615

Related US. Application Data [63] Continuation-in-part of Ser. No. 402,196, Oct. 1,

1973, abandoned.

[52] US. Cl. 220/203; 220/209; 220/360; 220/361; 220/367; 220/373; 220/DIG. 27 [51] Int. Cl. B65D 51/16 [58] Field of Search 220/373, 203, 209, 303, 220/366, 367, 360, 361, DIG. 27

[56] References Cited UNITED STATES PATENTS 2,732,971 1/1956 Holmes et al 220/203 2,990,971 7/1961 Enell 220/203 3,062,400 11/1962 Humbert... 220/203 3,381,846 5/1968 Lee 220/203 3,7l5,049 2/1973 McMullen et al. 220/367 Primary Examiner-William 1. Price Assistant ExaminerJoseph M. Moy Attorney, Agent, or FirmJohn R. Walker, Ill

[ 57] ABSTRACT A radiator cap adapted to allow coolant to forcibly be added to the interior of the radiator while the cap remains attached thereto. The cap includes the usual cap body that grips the filler neck for removable attachment thereto and a pressure plate assembly including a gasket and having a spring for yieldably urging the gasket against a seat portion of the tiller neck. The inventive cap also includes an outer tubular bypass communicating the interior of the radiator with the exterior thereof and a lower check valve selectively occluding the outer bypass. The lower check valve is automatically opened to admit air/fluid to pass into the radiator when the pressure therein drops below atmospheric pressure, i.e., the air/fluid passes through the outer bypass. The lower check valve may also be automatically opened by forcing fluid through the outer bypass thus allowing coolant to be admitted to the radiator without removing the cap therefrom.

An alternate embodiment additionally includes an upper check valve also selectively occluding the outer bypass. The upper end of the outer bypass is provided with a transverse aperture disposed above the upper check valve. The aperture is communicated with a recovery overflow tank and coolant is allowed to pass one way only through this aperture, i.e., from the tank into the radiator.

6 Claims, 5 Drawing Figures US. Patent 0a. 7,1975 Shet 2 of 3 3,910,451

I I 1 i l\\ QT Q Q!) \w a US. Patent 0a. 7,1975 Sheet 3 of 3 3,910,451

RADIATOR CAP CROSS REFERENCE TO RELATED APPLICATION BACKGROUND OF THE INVEN'ITON 1. Field of the Invention This invention relates to the field of radiator caps and is particularly directed toward radiator caps adapted to allow coolant to be added to the radiator while the cap remains attached thereto.

2. Description of the Prior Art Several attempts have been made during the past 50 years to perfect a radiator cap of the general type herein disclosed. This is evidenced by certain patents yet to be mentioned. However, for various reasons and in spite of these advancements the usual radiator caps, used for closing the filler necks of radiators containing coolant which is intended to cool liquid cooled internal combustion engines such as the engines used in presentday automobiles, do not allow coolant to be added to the interior of the radiator while the cap remains attached thereto. Yet almost everyone who has operated a vehicle for any length of time has experienced the age-old problem of engine overheating.

An overheated engine invariably forces a considerable amount of the coolant outwardly through the overflow line thus reducing the quantity of coolant which tends to compound the problem since the operating temperature of an internal combustioncngine is normally inversely proportional to the amount of coolant forced thcrethrough, i.e., the coolant being at a lower temperature than is the engine.

Further, most vehicle operators are familiar with the hazards involved in attempting to remove the usual radiator cap to add coolant to the radiator of an overheated engine. Since the usual radiator is pressurized, removing the cap causes instant release of extremely hot coolant which is spewed outwardly from the radiator making it very difficult if not impossible to avoid being burned by the hot coolant. This further loss of coolant raises the operating temperature of the engine even higher, oftentimes permanently damaging the engine.

The prior art includes the following U.S. patents: the Mills U.Sv Pat. No. 1,537,254; the Baskin et al, U.S. Pat. No. 1,548,244; the Ferrier U.S. Pat. No. 1,833,833; the Lisota U.S. Pat. No. 2,558,620; and the Boddie U.S. Pat. No. 3,380,619. None ofthe above references disclose or suggest applicants device. However. it should be mentioned that the Baskin et al, U.S. Pat. No. 1,548,244 which was filed in 1921 appears to be first in recognizing the problem or at least certain aspects of the problem herein disclosed. The complexity of certain of the prior radiator caps and the expense involved in manufacturing them probably are contributing factors as to why the usual present-day radiator cap does not incorporate the advantage of permitting coolant to be added to the radiator without removing the cap.

It should also be mentioned that the usual present day radiator cap incorporates structure to maintain a predetermined pressure on the coolant, i.e., it has been found that pressurization of cooling systems results in greater heat transfer efficiency. Accordingly, radiator caps of various pressures are available, e.g., normally ranging from 7 lbs. per square inch up to 15 lbs. per square inch. ln other words, once the pressure reaches the set limit, air and/or coolant may be exited from the radiator to prevent overpressurizing the radiator. On the other hand, these radiator caps also incorporate vacuum relief valves for allowing air to be admitted to the radiator as the radiator cools down, i.e., thus preventing a vacuum pressure within the radiator.

Another radiator cap, used recently in conjunction with a vented recovery overflow tank, additionally includes means for sealing the top of the filler neck as well as the bottom thereof, i.e., the bottom seal is spring loaded to pop open when the selected pressure is reached. This radiator cap assures that the coolant escaping from the radiator is transferred to a vented recovery overflow tank where it is temporarily stored. The only passageway for fluid to be readmitted to the radiator as it cools off is through the overflow tube which is communicated with the overflow tank. Therefore, the negative pressure developed within the radiator as it cools down draws fluid from the overflow tank into the radiator.

SUMMARY OF THE INVENTION The present invention is directed towards overcoming the disadvantages and problems relative to previous radiator caps. The present invention provides a radiator cap which incorporates the aforementioned advantages of the usual present-day radiator cap, i.e., the ability to pressurize the cooling system and provide vacuum relief. More specifically, the present invention is directed toward providing a radiator cap that is constructed along similar lines of the usual present-day radiator cap, thus minimizing the complexity and the cost thereof to enhance the probability of widespread use thereof. Additionally, the inventive radiator cap is adapted to allow coolant to be admitted to the radiator, even though it is overheated, without removing the cap therefrom.

The radiator cap of the present invention includes the usual cap body that grips the filler neck for remov able attachment thereto and a pressure plate assembly including a gasket and having a spring for yieldably urging the gasket against a seat portion of the filler neck. The instant cap also includes an outer tubular bypass which communicates the interior of the radiator with the exterior thereof and a lower check valve which selectively occludes the outer bypass. The lower check valve is automatically operable to an open position to admit air/fluid to pass into the radiator when the pressure therein drops below atmospheric pressure, i.e., the air/fluid passes through the outer bypass. The lower check valve may also be automatically operable to the open position by forcing fluid through the outer bypass thus allowing for coolant to be admitted to the radiator without removing the cap therefrom.

An alternate embodiment is also disclosed which is intended for use with the above described recovery overflow tank. The alternate embodiment additionally includes an upper check valve also selectively occluding the outer bypass. The upper end of the outer bypass is provided with a transverse hole disposed above the upper check valve and which opens into the filler neck. This transverse hole is communicated with the recovery overflow tank and coolant is allowed to pass one way only through this aperture, i.e., from the tank into the radiator. Also included is an eyelet rivet which functions as an inner tubular bypass to permit the transverse hole to be bypassed when adding coolant to the radiator without removing the cap therefrom. Addi-' tionally, a manually operable stopper is included which normally plugs the outermost end of the outer and inner tubular bypasses to enable the tiller neck to hold a slight vacuum for pulling fluid frornthe overflow tank. When it is desired to add fluid to the radiator.

while the cap remains attached thereto, the stopper is manipulated so as to unplug these inner and outer tubular bypasses, thus enabling fluid to be added in like manner as the principal embodiment. Unplugging these bypasses does not vent the radiator, therefore, hot coolant will not spew out of the radiator by manipulating the stopper.

DESCRIPTION OF THE DRAWING FIG. 1 is a sectional view of the radiator cap of the present invention shown suitably attached to the tiller neck of a radiator with the view being taken as on a vertical plane through the center line and showing coolant supply structure in phantom which may be used to add coolant to the radiator without removing the captherefrom.

FIG. 2 is an exploded elevational view of the radiator cap of the present invention.

FIG. 3 shows the coolant supply structure in phantom suitably engaging the device; also the path the replenishment coolant travels in bypassing the cap is shown.

FIG. 4 is a view similar to FIG. 1 depicting an alternate embodiment of the inventive radiator cap, shown in combination with a recovery overflow tank.

FIG. 5 is an exploded elevational view of the alter- I nate embodiment of the radiator cap of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The radiator closing device or radiator cap. 11 is intended for closing the tiller neck 13 of a radiator 15,

which contains coolant 17 used to cool a liquid cooled e.g. water, through the outer bypass means 35 thus al-.

5 fore, the arrows 41 in FIG. 3 synonymously illustrate engine (not shown). The filler neck 13'includes the The device 11' generally comprises a cap body 21 in- I eluding means, such as the inwardly directed flanges 23, 25, for gripping the tiller neck 13 thus removably attaching the device 11 to the radiator 15. Pressure plate means 27 are included having gasket means 29 and spring means 31 which yieldably urges the gasket means 29 against the seat means 19 thus sealing the interior 33 of the radiator 15 from without. Outer tubular bypass means 35 is included for communicating the interior 33 of the radiator with the exterior 37 thereof. Lower check valve means 39 is provided for selectively occluding the bypass means 35. The lower check valve means 39 is automatically operable to an open position as depicted in FIG. 3 of the drawing and characterized therein by the numeral 39' to admit air/fluid, indicated by the arrows 41, into the interior 33 of the radiator 15 when the pressure therein drops below atmospheric pressure. The air/fluid, shown by the arrows 41, passes through the outer bypass means 35. The lower check valve means 39 may also be automatically operated to the open position 39' by forcing fluid under pressure,

air, coolant, or simply water.

More specifically, the tiller neck 13 has a proximal end 43 and a distal end 45 with the seat means 19 being adjacent the distal end 45 and the flanges 23, 25 gripping the proximal end 43 in a well-known manner. Further, the spring means 31 preferably is a compression spring which is disposed subj acent the cap body 21 with the upper end, as at 47 thereof, restingly engaging the cap body 21 and the lower end, as at 49, of the spring means 31 restingly engaging the pressure plate member 51 of the pressure plate means 27. Accordingly, the pressure plate member 51 coacts with the spring means 31 for yieldably urging, the gasket means 29 tightly against the seat means 19 thus sealing the interior 33 of the radiator from without. It should be understood thatthe tension of the spring means 31' is predetermined so that when the pressure Within the radiator builds up to, a specified pressure the pressure plate member 51 pops up or moves toward the cap body 21 thus compressing the spring means 31 to allow an intermittent escapement of air and/or coolant from the. radiator 15. In other words, the tension on the spring means 31 determines the maximum pressure permitted to build up within the radiator 15.

From FIG. 1' of the drawing it may be seen that the outer, tubular bypass means 35 is disposed within the tiller neck 13 and extends from the pressure plate member 51 to the cap body 21. Accordingly, the cap body 21 and the pressure plate member 51 are provided with respective'apertures 53, 55 for receiving the outer, bypass means 35. More specifically, the lower end, as at 57, of the outer bypass means 35 extends through the aperture 55 and the upper end, as at 59,:of

the outer bypass means 35 extends through the aperture 53 with the spring means 31 being circumferentially disposed about the outer bypass means 35.

The device 11 also includes captive means 61 for attaching the cap body 21, the pressureplate means 27, and the spring means 31 one to the other in such a manner that the pressure plate means or member 51 is mov able yieldably towards the cap body 21 against the resistance of. the spring means 31. It should be understood that the captive means 61 is intended to include the latest developments inrthe state of the art for attaching the pressure plate member 51 to the cap body 21 in the above-described manner. In view of the above, I prefer to simply Show the captive means 61 as an enlarged portion of the upper end 59 of the outer bypass means 35 with the upper end 59 being free to slide to and fro within the aperture 53, i.e., as a result of pressure buildup in the interior 33 as above described.

On the other hand, the upper end 59 of the outer bypass means 35 may optionally be fixedly attached to the cap body 21 in any well-known manner as by brazing or the like. In this event, the pressure plate member 51 would be slidably received about the lower end 57 of the outer bypass means 35, i.e., thus enabling the pressure plate member 51 to slide along the lower end 57 as a result of the pressure buildup as above described.

In other words, the outer bypass means 35 and the pressure plate member 51 may be integrally formed or fixed one to the other in which case the upper end 59 is free to slide in the aperture 53 or if desirable, the pressure plate member 51 may be free to slide about the outer bypass means 35 as above described.

The lower check valve means 39 may be of any wellknown construction for selectively occluding the bypass means 35. Accordingly, sufficient disclosure should be evident by simply stating that the lower check valve means 39 preferably includes a main body member 63 which is conveniently attached to the pressure plate member 51 and includes a valve seat 65. Additionally, the lower check valve 39 includes a seal member 67, a seal actuating member 69, a compression spring 71, and a rivet 73. The rivet 73 captures the seal actuating member 69, the seal member 67, and the compression spring 71 to the main body member 63 in such a manner that the seal actuating member 69 is movable yieldably away from the main body member 63. It should also be mentioned that the main body member 63 is provided with a plurality of apertures as at 75 which are selectively closed and opened by the seal member 67, i.e., the lower check valve means 39 being moved to the open position shown by the numeral 39' (FIG. 3) when the pressure in the interior 33 of the radiator drops below atmospheric pressure as previously described Accordingly, the air/fluid, shown by the arrows 41 (FIG. 3), as well as the fluid under pressure or replenishment coolant 17 passes through the apertures 75 when admitted to the interior 33.

The device 11 preferably includes means, such as annular seal means 77, suitably disposed adjacent the exterior of the cap body 21 and conveniently attached thereto for sealably receiving certain replenishment coolant supply structure, for example, the end of a garden hose 79 or the like, which delivers the pressurized replenishment coolant 17 to the outer bypass means 35.

More specifically, the cap body 21 preferably is recessed as at 81 with the seal means 77 being fixedly attached to the exterior of the cap body 21 with the outer surface of the seal means preferably being flush with the exposed exterior surface of the cap body 21. The outer surface, as at 83, of the seal means 77 preferably is resilient (e.g., made out of rubber, plastic or the like) for scalable engagement with the coolant supply structure or garden hose and the like as the coolant supply structure 79 is manually urged thereagainst.

Accordingly, it will be appreciated that the coolant supply structure 79 need not be specially constructed or adapted with fittings or the like to force coolant 17 into the radiator 15. Therefore, the seal means 77 not only sealably engages the flat end of a garden hose but sealably engages limitless other typical nozzles and the like to facilitate the desired feature of instantly adapting the device 11 to an extremely wide variety of coolant supply structures 79. The ultimate objective of instantly adapting a wide variety of coolant supply structures 79 to the radiator cap 11 has the obvious advantage of minimizing the delay in replenishing the coolant 17 in an overheated radiator 15 without exposing anyone to the hazard of being scalded by the extremely hot coolant, i.c., as experienced when removing the usual well-known prior devices.

ALTERNATE EMBODIMENT Particular attention is now directed toward FlGS.'4 and 5 of the drawings wherein it may be seen that an alternate embodiment of the radiator cap is disclosed and is character referenced therein by the numeral 1 1 The radiator cap 11 is similar in some respects to the radiator cap 11, accordingly, the similar structure will be identified by identical numerals while structure peculiar to the radiator cap 11 will be fully disclosed and identified by numerals peculiar thereto.

The radiator cap 11' is intended to be'used in conjunction with the previously described radiator 15. However, in this embodiment the overflow tube 18 thereof is communicated with a vented recovery overflow tank 101. The radiator cap 11 assures that the coolant 17 escaping from the radiator 15 is transferred to the vented recovery overflow tank 101 where it is temporarily stored. The negative pressure developed within the radiator 15 by the normal cooling down process draws the coolant 17 from the overflow tank 101 back into the radiator 15 in a manner about to be described.

The usual filler neck 13 includes a previously described valve seat which will hereinafter be referred to as primary seat means also character referenced by the numeral 65. Additionally, the filler neck 13 includes secondary seat means, as at 103. The primary and secondary seat means 65, 103 coact with the device l 1' for sealing the respective lower and upper ends of the filler neck 13. The cap body 21 is provided with the aperture 53 and disposed about the aperture 53 is the previously described annular seal means 77. The radiator cap 11' is characterized by stopper means, as at 105 for selectively closing and opening the aperture 53. The stopper means 105 may simply include a lid member 107 which is pivotally attached to the cap body 21 by a vertical pivot pin 109. The lid member 107 preferably includes an annular shoulder, as at 111, which contiguously engages the annular seal means 77. Thus, the negative pressure developed in the interior 33 of the radiator 15 is readily captured in the filler neck 13 from whence it is communicated through the overflow tube 18 to the recovery tank 101.

The radiator cap 1 1 includes outer tubular bypassing means 35 which is very similar to the outer tubular bypass means 35 previously described. The bypass means 35' preferably is larger in diameter than is the bypass means 35. Further, the bypass means 35' is provided with at least one but preferably a plurality of transverse holes, as at 113, which are disposed adjacent the cap body 21 as clearly shown in FIGS. 4 and 5 of the drawings. The outer tubular bypass means 35' is disposed in the filler neck 13 and extends from the pressure plate means 27 to the cap body 21 for communicating the interior 33 of the radiator 15 with the exterior 37 thereof, in the same manner as previously described for the principal embodiment.

The radiator cap 11 includes upper check valve means, as at 115, selectively occluding the outer tubular bypass means 35. The upper check valve means 1 15 is disposed subjacent the transverse holes 113 and functions automatically for allowing one-way flow of coolant 17 through the transverse hole 113.

The radiator cap 11' also includes means, e.g., inner tubular bypass means 117, disposed within the outer tubular bypass means 35' and coacting with the upper check valve means 115 for isolating the upper interior of the outer tubular bypass means 35 from the lower interior thereof.

The radiator cap 1 1 includes the previously described check valve means 39 which hereinafter will be referred to as lower check valve means and is character referenced in FIGS. 4 and 5 of the drawings by the numeral 39. The lower check valve means 39 normally.

allows a positive pressure to build up within the interior 33 of the radiator 15. Additionally, the lower check valve means 39 is automatically operable to allow coolant 17 to pass from the recovery overflow tank 101 into the interior 33 of the radiator as the pressure therein drops below atmospheric pressure. In this regard, the coolant 17 passes through the overflow tube 18 into the filler neck 13, thence entering the outer tubular bypass means (through the transverse hole 113 therein), thence through or about the respective upper and lower check valve means 115, 39.'

The lower check valve means 39 is also automatically operable to allow coolant 17 to be added to the radiator 15 through the aperture 53 provided in the cap body 21.This may be accomplished by: First, opening the stopper means 105 while the device 11 remains at- I tached to the radiator 15; second, by forcing fluid, such as water under pressure, through the outer bypass meand 35' in the same manner as fully described above for the principal embodiment.

The upper check valve means 115 includes a flexible umbrella-like member 119 having an upper circular portion, as at 121, and a lower flared skirt-like portion, as at 123. The flared skirt-like portion 123 normally scalably engages the interior wall of the outer tubular bypass means 35 as clearly shown in FIG. 4 of the drawings. The circular portion ,121 is provided with an aperture 125 for receiving the. lower end of the inner tubular bypass means 1 17. The upper end of the inner tubular bypass means 117 extends upwardly through the aperture 53 provided in the cap body 21 and sealably engages the cap body 21. A positive pressure beneath the skirt-like portion 123 caused by forcing water or the like through the inner and outer tubular bypass means 117, 35 tends to expand the skirt-like portion. Thus, the water is precluded from exiting outwardly through the transverse hole 113 provided in the outer tubular bypass means 35. On the other hand, the skirtlike portion 123 is automatically collapsible inwardly to allow free passage thcreabout of the coolant 17 which enters the outer tubular bypass means 35, through the transverse holes 113 provided therein, i.e., the coolant 17 ultimately passes into the interior 33 of the radiator 15.

The means coacting with the upper check valve means 115 for isolating the upper interior of the outer tubular bypass means 35' from the lower interior thereof preferably includes the inner tubular bypass means 117. However, if desirable, the bypass means 1 17 may constitute a typical eyelet rivet which extends through the respective apertures 125, 53 provided in the circular portion 121 and the cap body 21. In this regard, the eyelet rivet conveniently fixedly attaches the upper check valve means 115 to the cap body 21in a manner well known to those skilled in the art.

The radiator cap 11 preferably includes O-ring means, as at 127, circumferentially engaging the outer tubular bypass means 35 for sealing the pressure plate means 27 to the outer tubular bypass means 35. in this regard, a washer 129 is included which is chamfered, as at 131, to direct and urge the O'ring 127 inwardly against the outer tubular bypass means 35, i.e., the

spring 31 restingly engages the washer 129,. Thus, the pressure plate means 27 is free to slide up and down as the pressure in the radiator varies.

The arrows 41 depicted in FIG. 4 of the drawings clearly show the path in which fluid travels through the outer tubular. bypass means 35" and the lower check valve means 29 when water under pressure is added to the radiator while the device 11" remains attached thereto. Additionally, arrows character referenced by the numeral 41' clearly depict the path the coolant 17 travels when a positive pressure develops in the interior 33'of the radiator 15. Thus, this causes the coolant to pass outwardly through the overflow tube 18 and be temporarily stored within the overflow tank 101. Further, arrows character referenced by the numeral 41" clearly depict the path the coolant travels when being returned from the overflow tank 101 to the interior 33 of the radiator 15, i.e., as the radiator 15 cools down.

Although the invention has been described and illustrated with respect to preferred embodiments thereof, it is not to be so limited since changes and modifications may be made therein which are within the full intended scope of the invention.

I claim:

1. In combination witha vented recovery overflow tank and a radiator communicated one with the other through the tiller neck of the radiator, of a closure device for closing the filler neck of the radiator and allowing coolant to be admitted to the interior of the radiator while said closure device remains attached to the radiator, said device comprising a cap body provided with an aperture disposed concentrically thereof, said filler neck including primary and secondary seat means coacting with said device for sealing the respective lower and upper ends of said filler neck, pressure plate means disposed adjacent said primary seal means and including spring means for yieldably allowing pressurized coolant to pass from said radiator into said filler neck thence into said recovery overflow tank, outer tubular bypass means disposed within said filler neck and extending from said pressure plate means to said cap body for communicating the'interior of said radiator with the exterior thereof, stopper means for selectively closing and opening said outer tubular bypass means, said pressure plate means being provided with an aperture for receiving the lowerend of said outer bypass meanswith the upper end of said outer bypass means extending through said aperture in said cap body, said outer tubular bypass means being provided'with at least one transverse hole opening into said filler neck, upper check valve means selectively occluding said outer tubular bypass means and being disposed therein subjacent said transverse hole for allowing one-way flow of coolant through said transverse hole, and lower check valve means for normally allowing a positive pressure within the interior of the radiator, said lower check valve means being operable selectively to allow coolant to pass from said recovery overflow tank into the interior of the radiator as the pressure therein drops below atmospheric pressure and by forcing fluid through said outer bypass means.

2. The combination of claim 1 in which is included.

means coacting with said upper check valve means for isolating the upper'interior of said outer tubular bypass means from the lower interior thereof.

3. The combination of claim 2 in which said means coacting with said upper check valve meansincludes inner tubular bypass means.

4. The combination of claim 2 in which said upper check valve means includes a flexible unbrellalike member having an upper circular portion and a lower flared skirtlike portion, said flared skirtlike portion normally sealably engaging the interior wall of said outer tubular bypass means, said circular portion being provided with an aperture for receiving the lower end of said inner tubular bypass means, the upper end of said inner tubular bypass means extending through said aperture provided in said cap body and sealably engaging said cap body, said upper check valve means precluding fluid which passes through said inner and outer tubular bypass means from exiting outwardly through said transverse hole provided in said outer tubular bypass means, and said skirtlike portion thereof being automatically collapsible to allow free passage thereabout of coolant entering said outer tubular bypass means through said transverse hole provided therein to ultimately pass into the interior of the radiator.

5. The combination of claim 4 in which said inner tubular bypass means includes an eyelet rivet extending through the apertures provided in the circular portion of the upper check valve means and the cap body, said eyelet rivet fixedly attaching said upper check valve means to said cap body.

6. The combination of claim 1 in which is included O-ring means circumferentially engaging said outer tubular bypass means for sealing said pressure plate means to said outer tubular bypass means, said pressure plate means being free to slide up and down as the pressure in the radiator varies between predetermined limltS. 

1. In combination with a vented recovery overflow tank and a radiator communicated one with the other through the filler neck of the radiator, of a closure device for closing the filler neck of the radiator and allowing coolant to be admitted to the interior of the radiator while said closure device remains attached to the radiator, said device comprising a cap body provided with an aperture disposed concentrically thereof, said filler neck including primary and secondary seat means coacting with said device for sealing the respective lower and upper ends of said filler neck, pressure plate means disposed adjacent said primary seal means and including spring means for yieldably allowing pressurized coolant to pass from said radiator into said filleR neck thence into said recovery overflow tank, outer tubular bypass means disposed within said filler neck and extending from said pressure plate means to said cap body for communicating the interior of said radiator with the exterior thereof, stopper means for selectively closing and opening said outer tubular bypass means, said pressure plate means being provided with an aperture for receiving the lower end of said outer bypass means with the upper end of said outer bypass means extending through said aperture in said cap body, said outer tubular bypass means being provided with at least one transverse hole opening into said filler neck, upper check valve means selectively occluding said outer tubular bypass means and being disposed therein subjacent said transverse hole for allowing oneway flow of coolant through said transverse hole, and lower check valve means for normally allowing a positive pressure within the interior of the radiator, said lower check valve means being operable selectively to allow coolant to pass from said recovery overflow tank into the interior of the radiator as the pressure therein drops below atmospheric pressure and by forcing fluid through said outer bypass means.
 2. The combination of claim 1 in which is included means coacting with said upper check valve means for isolating the upper interior of said outer tubular bypass means from the lower interior thereof.
 3. The combination of claim 2 in which said means coacting with said upper check valve means includes inner tubular bypass means.
 4. The combination of claim 2 in which said upper check valve means includes a flexible unbrellalike member having an upper circular portion and a lower flared skirtlike portion, said flared skirtlike portion normally sealably engaging the interior wall of said outer tubular bypass means, said circular portion being provided with an aperture for receiving the lower end of said inner tubular bypass means, the upper end of said inner tubular bypass means extending through said aperture provided in said cap body and sealably engaging said cap body, said upper check valve means precluding fluid which passes through said inner and outer tubular bypass means from exiting outwardly through said transverse hole provided in said outer tubular bypass means, and said skirtlike portion thereof being automatically collapsible to allow free passage thereabout of coolant entering said outer tubular bypass means through said transverse hole provided therein to ultimately pass into the interior of the radiator.
 5. The combination of claim 4 in which said inner tubular bypass means includes an eyelet rivet extending through the apertures provided in the circular portion of the upper check valve means and the cap body, said eyelet rivet fixedly attaching said upper check valve means to said cap body.
 6. The combination of claim 1 in which is included O-ring means circumferentially engaging said outer tubular bypass means for sealing said pressure plate means to said outer tubular bypass means, said pressure plate means being free to slide up and down as the pressure in the radiator varies between predetermined limits. 